您可以使用包 javafx.scene.image 中的JavaFX提供的类来加载和修改图像. JavaFX支持像 Bmp，Gif，Jpeg，Png 这样的图像格式.
本章教你如何将图像加载到JavaFX，如何投影图像多个视图以及如何更改图像的像素.
加载图像
您可以通过实例化名为
对于类的构造函数，您必须传递以下任何一个和减号;
要加载的图像的 InputStream 对象，或
包含图像URL的字符串变量.
//Passing FileInputStream object as a parameter FileInputStream inputstream = new FileInputStream("C:\\images\\image.jpg"); Image image = new Image(inputstream); //Loading image from URL //Image image = new Image(new FileInputStream("url for the image));加载图像后，您可以通过实例化 ImageView 类并将图像传递给其构造函数来设置图像视图，如下所示 :
ImageView imageView = new ImageView(image);
示例
以下是演示如何在JavaFX中加载图像并设置视图的示例.
将此代码保存在名为 ImageExample.java 的文件中.
import java.io.FileInputStream; import java.io.FileNotFoundException; import javafx.application.Application; import javafx.scene.Group; import javafx.scene.Scene; import javafx.scene.image.Image;import javafx.scene.image.ImageView; import javafx.stage.Stage; public class ImageExample extends Application { @Override public void start(Stage stage) throws FileNotFoundException { //Creating an image Image image = new Image(new FileInputStream("path of the image")); //Setting the image view ImageView imageView = new ImageView(image); //Setting the position of the image imageView.setX(50); imageView.setY(25); //setting the fit height and width of the image view imageView.setFitHeight(455); imageView.setFitWidth(500); //Setting the preserve ratio of the image view imageView.setPreserveRatio(true); //Creating a Group object Group root = new Group(imageView); //Creating a scene object Scene scene = new Scene(root, 600, 500); //Setting title to the Stage stage.setTitle("Loading an image"); //Adding scene to the stage stage.setScene(scene); //Displaying the contents of the stage stage.show(); } public static void main(String args[]) { launch(args); } }使用以下命令从命令提示符编译并执行保存的java文件.
Javac ImageExample.java java ImageExample
执行时，上述程序生成一个JavaFX窗口，如下 :
多个视图图像
您还可以为同一场景中的图像设置多个视图.以下程序是演示如何在JavaFX中为场景中的图像设置各种视图的示例.
将此代码保存在名为 MultipleViews.java的文件中.
import java.io.FileInputStream; import java.io.FileNotFoundException; import javafx.application.Application; import javafx.scene.Group; import javafx.scene.Scene; import javafx.scene.image.Image; import javafx.scene.image.ImageView; import javafx.stage.Stage; public class MultipleViews extends Application { @Override public void start(Stage stage) throws FileNotFoundException { //Creating an image Image image = new Image(new FileInputStream("file path")); //Setting the image view 1 ImageView imageView1 = new ImageView(image); //Setting the position of the image imageView1.setX(50); imageView1.setY(25); //setting the fit height and width of the image view imageView1.setFitHeight(300); imageView1.setFitWidth(250); //Setting the preserve ratio of the image view imageView1.setPreserveRatio(true); //Setting the image view 2 ImageView imageView2 = new ImageView(image); //Setting the position of the image imageView2.setX(350); imageView2.setY(25); //setting the fit height and width of the image view imageView2.setFitHeight(150); imageView2.setFitWidth(250); //Setting the preserve ratio of the image view imageView2.setPreserveRatio(true); //Setting the image view 3 ImageView imageView3 = new ImageView(image); //Setting the position of the image imageView3.setX(350); imageView3.setY(200); //setting the fit height and width of the image view imageView3.setFitHeight(100); imageView3.setFitWidth(100); //Setting the preserve ratio of the image view imageView3.setPreserveRatio(true); //Creating a Group object Group root = new Group(imageView1, imageView2, imageView3); //Creating a scene object Scene scene = new Scene(root, 600, 400); //Setting title to the Stage stage.setTitle("Multiple views of an image"); //Adding scene to the stage stage.setScene(scene); //Displaying the contents of the stage stage.show(); } public static void main(String args[]) { launch(args); } }使用以下命令从命令提示符编译并执行保存的java文件.
Javac MultipleViews.java java MultipleViews
执行时，上述程序生成JavaFX窗口如下 :
写入像素
JavaFX提供了名为 PixelReader 和 PixelWriter 类的类来读取和写入图像的像素. WritableImage 类用于创建可写图像.
以下是演示如何读取和写入图像像素的示例.在这里，我们正在读取图像的颜色值并使其变暗.
将此代码保存在名为 WritingPixelsExample.java 的文件中.
import java.io.FileInputStream; import java.io.FileNotFoundException; import javafx.application.Application; import javafx.scene.Group; import javafx.scene.Scene; import javafx.scene.image.Image; import javafx.scene.image.ImageView; import javafx.scene.image.PixelReader; import javafx.scene.image.PixelWriter; import javafx.scene.image.WritableImage; import javafx.scene.paint.Color; import javafx.stage.Stage; public class WritingPixelsExample extends Application { @Override public void start(Stage stage) throws FileNotFoundException { //Creating an image Image image = new Image(new FileInputStream("C:\\images\\logo.jpg")); int width = (int)image.getWidth(); int height = (int)image.getHeight(); //Creating a writable image WritableImage wImage = new WritableImage(width, height); //Reading color from the loaded image PixelReader pixelReader = image.getPixelReader(); //getting the pixel writer PixelWriter writer = wImage.getPixelWriter(); //Reading the color of the image for(int y = 0; y < height; y++) { for(int x = 0; x < width; x++) { //Retrieving the color of the pixel of the loaded image Color color = pixelReader.getColor(x, y); //Setting the color to the writable image writer.setColor(x, y, color.darker()); } } //Setting the view for the writable image ImageView imageView = new ImageView(wImage); //Creating a Group object Group root = new Group(imageView); //Creating a scene object Scene scene = new Scene(root, 600, 500); //Setting title to the Stage stage.setTitle("Writing pixels "); //Adding scene to the stage stage.setScene(scene); //Displaying the contents of the stage stage.show(); } public static void main(String args[]) { launch(args); } }使用以下命令从命令提示符编译并执行保存的java文件.
Javac WritingPixelsExample.java java WritingPixelsExample
执行时，上述程序生成一个JavaFX窗口如下 :
